mm/hwpoison-inject.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Inject a hwpoison memory failure on a arbitrary pfn */
   3 #include <linux/module.h>
   4 #include <linux/debugfs.h>
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <linux/swap.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/hugetlb.h>
  10 #include "internal.h"
  11
  12 static struct dentry *hwpoison_dir;
  13
  14 static int hwpoison_inject(void *data, u64 val)
  15 {
  16         unsigned long pfn = val;
  17         struct page *p;
  18         struct folio *folio;
  19         int err;
  20
  21         if (!capable(CAP_SYS_ADMIN))
  22                 return -EPERM;
  23
  24         if (!pfn_valid(pfn))
  25                 return -ENXIO;
  26
  27         p = pfn_to_page(pfn);
  28         folio = page_folio(p);
  29
  30         if (!hwpoison_filter_enable)
  31                 goto inject;
  32
  33         shake_folio(folio);
  34         /*
  35          * This implies unable to support non-LRU pages except free page.
  36          */
  37         if (!folio_test_lru(folio) && !folio_test_hugetlb(folio) &&
  38             !is_free_buddy_page(p))
  39                 return 0;
  40
  41         /*
  42          * do a racy check to make sure PG_hwpoison will only be set for
  43          * the targeted owner (or on a free page).
  44          * memory_failure() will redo the check reliably inside page lock.
  45          */
  46         err = hwpoison_filter(&folio->page);
  47         if (err)
  48                 return 0;
  49
  50 inject:
  51         pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  52         err = memory_failure(pfn, MF_SW_SIMULATED);
  53         return (err == -EOPNOTSUPP) ? 0 : err;
  54 }
  55
  56 static int hwpoison_unpoison(void *data, u64 val)
  57 {
  58         if (!capable(CAP_SYS_ADMIN))
  59                 return -EPERM;
  60
  61         return unpoison_memory(val);
  62 }
  63
  64 DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  65 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  66
  67 static void __exit pfn_inject_exit(void)
  68 {
  69         hwpoison_filter_enable = 0;
  70         debugfs_remove_recursive(hwpoison_dir);
  71 }
  72
  73 static int __init pfn_inject_init(void)
  74 {
  75         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  76
  77         /*
  78          * Note that the below poison/unpoison interfaces do not involve
  79          * hardware status change, hence do not require hardware support.
  80          * They are mainly for testing hwpoison in software level.
  81          */
  82         debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
  83                             &hwpoison_fops);
  84
  85         debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
  86                             &unpoison_fops);
  87
  88         debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
  89                            &hwpoison_filter_enable);
  90
  91         debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
  92                            &hwpoison_filter_dev_major);
  93
  94         debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
  95                            &hwpoison_filter_dev_minor);
  96
  97         debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
  98                            &hwpoison_filter_flags_mask);
  99
 100         debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
 101                            &hwpoison_filter_flags_value);
 102
 103 #ifdef CONFIG_MEMCG
 104         debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
 105                            &hwpoison_filter_memcg);
 106 #endif
 107
 108         return 0;
 109 }
 110
 111 module_init(pfn_inject_init);
 112 module_exit(pfn_inject_exit);
 113 MODULE_DESCRIPTION("HWPoison pages injector");
 114 MODULE_LICENSE("GPL");